1. Field of the Invention
With reference to the classification of art as noted by the Examiner, this method invention is believed to be found in the class entitled, "Plastic and Nonmetallic Article Shaping or Treating Processes" and in the subclass entitled, "Vacuum treatment of work".
2. Description of the Prior Art
Apparatus for centrifugally casting thermosetting plastics and the like are well known and have been shown in issued patents. Some prior art showings believed to be pertinent include U.S. Pat. No. 3,601,857 issued to HAMPEL on Aug. 31, 1971 which discloses materials for making a mold; U.S. Pat. No. 3,850,902 issued to METCALFE, et al., on Nov. 29, 1974 disclosing a process for casting parts; U.S. Pat. No. 4,002,418 issued to WALLACE on Jan. 11, 1977 and U.S. Pat. No. 4,034,955 also issued to WALLACE on July 12, 1977. Each of these patents discloses apparatus for centrifugally casting parts and the clamping of the casting molds; U.S. Pat. No. 4,063,863 as issued to HILMOE on Dec. 20, 1977 disclosing a centrifugal casting machine having a vacuum assist.